Electrode structure of the touch panel, method thereof and touch panel

ABSTRACT

An electrode structure is provided. The electrode structure comprises a plurality of first conductive cells and second conductive cells separated from each other and disposed on a substrate; a plurality of first conductive lines connecting adjacent said first conductive cells and a plurality of second conductive lines connecting adjacent said second conductive cells; wherein each said second conductive line comprises a conducting element and a pair of second conductive branches disposed at two sides of said conducting elements and connecting said conducting element to adjacent said second conductive cells; said first conductive lines and said second conductive lines are insulated and intersected. The method of forming an electrode structure is also provided.

BACKGROUND OF THE INVENTION

This application is a Divisional Application of Ser. No. 13/210,394,filed Aug. 16, 2011 by the present inventors, Which is incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to a touch device, especially to anelectrode structure of the touch panel, the method thereof and the touchpanel.

DESCRIPTION OF THE RELATED ART

The touch panels have been widely used in various electronic devices inrecent years. These can even replace the conventional keyboards and miceto control the electronic devices.

The conventional touch panel includes an active area placed on asubstrate. The active area is usually covered with transparentconductive film. When the fingers or stylus touch the active area, thetouch signals are created for the subsequent processes.

There are many types of touch sensing methods, such as resistive sensingtype, capacitive sensing type, acoustic wave sensing type, opticalsensing type and the like. For the capacitive sensing method, the touchpanel perceives touch locations by detecting the change in capacitancedue to the proximity of conductive objects such as metals or fingers.The capacitive touch panel is widely adopted because of the advantageslike high rigidity, accuracy and longevity, accurate response time,operating temperature and initializing force.

Various types of touch panels with different electrode patterns arenewly developed for detecting the touch locations of the fingers orconductive objects on the touch surface. For example, U.S. Pat. No.6,970,160 disclosed a lattice touch-sensing system for detecting aposition of a touch on a touch-sensitive surface. The latticetouch-sensing system stem may include two capacitive sensing layers,separated by an insulating material, where each layer consists ofsubstantially parallel conducting elements, and the conducting elementsof the two sensing layers are substantially orthogonal to each other.Each element may comprise a series of diamond shaped patches that areconnected together with narrow conductive rectangular strips. Eachconducting element of a given sensing layer is electrically connected atone or both ends to a lead line of a corresponding set of lead lines. Acontrol circuit may also be included to provide an excitation signal toboth sets of conducting elements through the corresponding sets of leadlines, to receive sensing signals generated by sensor elements when atouch on the surface occurs, and to determine a position of the touchfrom the sensing signals.

Although a series of diamond shaped patches of the touch-sensing systemare disclosed in above-mentioned patent, the lattice touch-sensingsystem includes two capacitive sensing layers, separated by aninsulating material. Thus, the lattice touch-sensing system is too.thick to meet the requirement of reducing the thickness of thecapacitive touch panel. Besides, the conventional capacitive touch panelis manufactured by forming the two capacitive sensing layers on the twosides of a substrate and connecting each series of diamond shapedpatches with lead lines through the holes on the substrate. Therefore,the manufacturing process is complicated.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide an electrodestructure to reduce the thickness of the touch panel and simplify themanufacturing process.

The electrode structure comprises a plurality of first conductive cellsand second conductive cells separated from each other and disposed on asubstrate; a plurality of first conductive lines connecting adjacentsaid first conductive cells and a plurality of second conductive linesconnecting adjacent said second conductive cells; wherein each saidsecond conductive line comprises a conducting element and a pair ofsecond conductive branches disposed at two sides of said conductingelements and connecting said conducting element to adjacent said secondconductive cells; said first conductive lines and said second conductivelines are insulated and intersected.

The other objective of the present invention is to provide a method offanning an electrode structure.

The method of forming an electrode structure comprises: (a) forming aplurality of first conductive cells, a plurality of first conductivelines connecting adjacent said first conductive cells and a plurality ofsecond conductive cells; (b) forming a plurality of conducting elementsinsulated from said first conductive lines; and (c) forming a pluralityof pairs of second conductive branches over said first conductive linesto connect said second conductive cells with said conducting elements.

By means of the present invention, the first conductive cells and thesecond conductive cells are disposed on the same surface of thesubstrate, so the thickness of touch panel including the electrodestructure is reduced. Moreover, each second conductive line is dividedinto a conducting element and a pair of second conductive branches, andthe length of a pair of second conductive branches is less than thedistance between two adjacent second conductive cells. Thus, thevisibility of the second conductive lines is reduced to improve theappearance of the touch panel including the electrode structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The skilled artisan will understand that the drawings, described below,are for illustration purposes only The drawings are not intended tolimit the scope of the present teachings in any way. Like referencenumerals designate corresponding parts throughout the several views.

FIG. 1 is a schematic view of the electrode structure of the presentinvention;

FIG. 2 is a schematic enlarged view of part A of FIG. 1;

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 shows the electrode structure. The electrode structure 300 ofcapacitive touch panel is disposed on a substrate (not shown), such asglass. The electrode structure 300 comprises a plurality of firstconductive cells 311 and second conductive cells 312, which areseparated from each other. The first conductive cells 311 constitute atleast one group of first electrode groups 310, while the secondconductive cells 312 constitute at least one group of second electrodegroups 320. The first electrode groups 310 are insulated from the secondelectrode groups 320. Two adjacent first conductive cells 311 in any onefirst electrode group 310 are connected by a plurality of firstconductive lines 312, and two adjacent second conductive cells 321 inany one second electrode group 320 are connected by a plurality ofsecond conductive lines 322. A plurality of signal traces (not shown)disposed on the border of the electrode structure connect the firstelectrode cells 311 and the second electrode cells 321 to a controller(not shown) to transmit touch sensing signals.

Referring to FIG. 1 as well as FIG. 2, each second conductive line 322includes a conducting element 324 and a pair of second conductivebranches 323. A window 341 is formed in each first conductive line 312,and a conducting element 324 is located in each window 341. A closed gap342 is formed between each first conductive line 312 and the conductingelements 324 in related first conductive line 312 to make the firstconductive line 312 be separated and insulated from the conductingelement 324. Two second conductive branches 323 in each pair of secondconductive branches 323 are disposed at two sides of the conductingelement 324 and connect the conducting element 324 to two adjacentsecond conductive cells 321. In other word, one end of each individualsecond conductive branch 323 connects one conducting element 324, whileanother end of it connects one second conductive cell 321. Therefore,the second conductive cells 321 in one of the second electrode groups320 are connected by pairs of second conductive branches 323 and theconducting elements 324 in series to transmit the touch sensing signalsto the controller.

Each second conductive branch 323, intersected with the first conductiveline 312, is insulated from the first conductive lines 312 by aninsulating layer 330. The insulating layer 330 made of transparentinsulating material includes a plurality of insulating elements 331located at the intersection of each second conductive branch 323 and thefirst conductive line 312, by which the each second conductive branch323 is insulated from the first conductive lines 312.

The first conductive cells 311 and the second conductive cells 321 areall placed on the same surface of the substrate (not shown), so thefirst electrode groups 310 and the second electrode groups 320 areplaced on the surface of the substrate. Thus, the thickness of touchpanel including the electrode structure 300 can be reduced, and themanufacturing process can be

When the touch panel with the electrode structure 300 of the presentinvention is touched, the touch location covers at least one firstconductive cell 311 of the first electrode groups 310 and at least onesecond conductive cell 321 of the second electrode groups 320. A mutualcapacitance created between the covered first conductive cell 311 andthe covered second conductive cell 321 indicates a touch signal which istransmitted to the controller by the signal traces. Thus, the touchlocation is calculated and determined by the controller.

The first conductive cells 311, the second conductive cells 321, thefirst conductive lines 312, the conducting elements 324 and theindividual second conductive lines 323 are made of transparentconductive materials, which can be selected from a group of Indium TinOxide (ITO), Indium Zinc Oxide (IZO) or Aluminum Zinc Oxide (AZO).Besides, the conducting elements 324 can be made of metal.

The geometrical shape of the first conductive cells 311 and the secondconductive cells 312 can be diamond, hexagon, octagon, rectangle,triangle and so on.

Another embodiment of the present invention is provided, the differenceof which in contrast with the above-mentioned embodiment is that thefirst conductive lines 312 and the pairs of second conductive branches323 are placed in reverse order. The pairs of second conductive branches323 are placed on the surface of the substrate. The insulating elements331 are located on the pairs of second conductive branches 323. Thefirst conductive lines 312 are placed on the insulating elements 331.

The pairs of second conductive branches 323 are preferably made ofmetal, such as copper, silver, aluminum and so on. Because of the betterconnectivity of metal than that of ITO, the connectivity of the pairs ofsecond conductive branches 323 is increased to prevent them fromcracking at junction of the pairs of second conductive branches 323 andthe insulating elements 331. Besides, the conductivity of metal is alsobetter than that of ITO. As each pair of second conductive branches 323is connected by the conducting element 324, the length D1+D2 of twosecond conductive branches 323 is less than the distance L between twoadjacent second conductive cells 321, which reduces the visibility ofthe second conductive branches 323.

According to various design requirements, the two second conductivebranches 323 belonging to each pair of second conductive lines 322 canbe aligned or staggered with each other. Besides, the location and sizeof the second conductive branches 323 can be adjusted. For each secondconductive line 322, the number of the pairs of the second conductivebranches 323 can be more than one. The more the pairs of the secondconductive branches 323, the better the conductivity of the secondconductive lines 322 is. If one of the second conductive branches 323 isbroken, the other one can still keep the second electrode groups 320working as usual.

The electrode structure 300 provided by the present invention can beformed on a substrate by etching, sputtering, printing and so on.Etching the electrode structure 300 is taken as an example to describe amethod of forming the electrode structure 300 on the substrate. Themethod includes the following steps:

Firstly, a conductive film (such as 110) is coated on a cleanedsubstrate (such as glass). On the surface of the conductive film, a maskis printed by screen printing to cover parts of the conductive film andetch the uncovered parts of that. After etching, the first conductivecells 311, the second conductive cells 321 and the first conductivelines 312 connecting adjacent first conductive cells 311 are formed onthe substrate. Furthermore, the window 341 is formed in each firstconductive line 312.

Secondly, each conducting element 324 is formed in each window 341 andthe closed gap 342 is formed to insulate each conducting element 324from each related first conductive line 312. In preferred embodiment,when the material of the conducting elements 324 is the same as that ofthe first conductive cells 311, the second conductive cells 321 and thefirst conductive lines 312, the conducting elements 324 can be formed byetching simultaneously when the first conductive cells 311, the secondconductive cells 321 and the first conductive lines 312 are formed informer step. Thus, the steps of forming the electrode structure 300 canbe reduced.

Thirdly, an insulating layer 330 including a plurality of insulatingelements 331 is formed on the etched conductive film. Each insulatingelement 331 is located on the first conductive lines 312. The insulatingelements 331 are made of transparent insulating material.

Finally, the second conductive branches 323 are formed on the insulatingelements 331. One end of each second conductive branch 323 connects thesecond conductive cell 321, while the other end connects the conductingelement 324, so that the second conductive cells 321 can be connected inseries.

Furthermore, the method of forming the electrode structure 300 includesa step of forming the signal traces on the border of the electrodestructure 300. The first electrode cells 310 and the second electrodecells 320 connect to the periphery signal traces respectively (notshown).

The method of forming the electrode structure 300 provided in anotherembodiment can be implemented in reversed order. Firstly, the secondconductive branches 323 are formed on a substrate; secondly, a pluralityof insulating elements 331 of the insulating layer 330 is fanned on thesecond conductive branches 323; thirdly, the first conductive cells 311,the second conductive cells 321, the first conductive lines 312 and theconducting elements 324 are formed on the substrate, the firstconductive lines 312 are located on the insulating elements 331.

Moreover, the present invention also provides a touch panel includingthe electrode structure 300. The touch panel includes a substrate (notshown), such as glass, the electrode structure 300 for generating touchsensing signals, and a controller (not shown) for receiving andprocessing the touch sensing, signals.

While certain embodiments have been shown and described, variousmodifications and substitutions may be made thereto without departingfrom the spirit and scope of the invention. Therefore, it is to beunderstood that the present invention has been described by way ofillustration and not limitations.

What is claimed is:
 1. A method of forming an electrode structure,comprising steps of: a) forming a plurality of first conductive cells, aplurality of first conductive lines connecting adjacent said firstconductive cells and a plurality of second conductive cells; b) forminga plurality of conducting elements insulated from said first conductivelines; c) forming a plurality of pairs of second conductive branchesover said first conductive lines to connect said second conductive cellswith said conducting elements.
 2. The method of forming an electrodestructure of claim 1, further comprising a step of forming an insulatinglayer between said first conductive lines and said second conductivebranches.
 3. The method of forming an electrode structure of claim 2,wherein said insulating layer comprises a plurality of insulatingelements.
 4. The method of forming an electrode structure of claim 1,wherein said step a) and said step b) are implemented together.
 5. Themethod of forming an electrode structure of claim 1, further comprisinga step of forming a plurality of signal traces connecting said firstconductive cells and said second conductive cells on border of saidelectrode structure.
 6. The method of forming an electrode structure ofclaim 1, wherein a window is formed in each said first conductive linein said step (a); and each said conducting element is located in saidwindow with a closed gap formed between said conducting element and saidfirst conductive line in step (b).